Please keep in mind that the following data are from a test unit reviewed by Golden Ears - the test unit is not necessarily a representative sample of the model being reviewed.

When headphone out was tested, the internal mixer was set -3dB so as to counteract the amplifier’s gain.

1. Digital Input Test

1.1. XLR Input (AES/EBU)

Sampling Frequency : 96kHz / APRIL MUSIC - EXIMUS DP1

Test Mode : 24bit, 96kHz

1.2. Coaxial Input (SPDIF)

Sampling Frequency : 96kHz / APRIL MUSIC - EXIMUS DP1

Test Mode : 24bit, 96kHz

1.3. Optical Input (SPDIF)

Sampling Frequency : 96kHz / APRIL MUSIC - EXIMUS DP1

Test Mode : 24bit, 96kHz

1.4. USB Input

Sampling Frequency : 192kHz / APRIL MUSIC - EXIMUS DP1

Test Mode : 24bit, 96kHz

1.4.1 Upsampling effect in USB input (Test Mode : 24bit, 44.1kHz)

<note>

There is slight roll-off in high frequency range with USB input. Upsampling makes it disappear somehow.

Test Mode : 24bit, 44.1kHz

A given headphone output may accommodate many different headphones - in general, a smaller load impedance (on headphones) will lead to a larger sound, but at cost of accuracy in measurable data due to the increased current - this cost usually manifests in an increasingly weak bass and elevated crosstalk values as the load impedance decreases. The purpose of the tests to follow is to see how these values change as a function of impedance.

1. Headphone Output

R16:16Ω / R33:33Ω / R62:62Ω / R250:250Ω

Sampling Frequency : 44.1kHz / APRIL MUSIC - EXIMUS DP1

R16:16Ω / R33:33Ω / R62:62Ω / R250:250Ω

Test Mode : 24bit, 44.1kHz

1. Digital Input Test (Optical)

Sampling Frequency : 96kHz / APRIL MUSIC - EXIMUS DP1

Sampling Frequency : 96kHz / APRIL MUSIC - EXIMUS DP1

2. Analog Input Test

2.1. RCA Input

Sampling Frequency : 44.1kHz / APRIL MUSIC - EXIMUS DP1

3. FILTER Test (Bass Boost)

Sampling Frequency : 44.1kHz / APRIL MUSIC - EXIMUS DP1

A lower impedance is desirable on the headphone outputs of amplifiers. The output impedance is closely related to the damping factor, and is one of the most important parameters that determine headphones' performance - desktop amps tend to exhibit high impedance values, corresponding to poor performance.